System for calculating and displaying cable payout from a rotatable drum storage device

Abstract

A system for sensing, computing, and displaying the length and the speed of chain or cable payout or reel in. The system employs only a single sensor which measures cable drum movement. The calculation function is accomplished by a microprocessor or minicomputer which is programmed with the basic dimensions of the cable and cable drum and with the required calculation formulae. A display gives continuous readout to the operator of the cable payout and speed values from a predetermined cable reference point. The system is directly employable in drum payout and recovery systems regardless of their application. The cable references may be of steel, rope or even chain and the system may be incorporated in helicopter or aircraft cable systems, mine hoists or elevator systems wherever a precise control or readout of cable payout is required.

We claim: 
     
       1. A system operable in conjunction with a plurality of cable feed means of the type which includes a cable, a plurality of rotatable drum means, each drum means having a drive means and a core with a predetermined length and diameter for storing and feeding cable and having edge flanges for retaining said cable thereon in a plurality of layers each having a predetermined diameter and number of wraps per layer, for precisely measuring length of cable feed and current feed rate, the system comprising: a drilling vessel anchored by said plurality of cable feed means;   a plurality of sensor means adapted to detect angular rotation of each of said drum means, and to provide signals corresponding to increments of rotation of said drum means; and   a computer means, coupled to all of said sensor means and adapted to receive inputs of said signals corresponding to said incremental angular rotation of said drum means from said sensor means for providing output signals indicating current feed rate and the length of cable feed from said rotatable drum means and for controlling the length of cable fed from and the current feed rate of each of said rotatable drum means, whereby said drilling vessel is moved in a desired direction by appropriately infeeding or paying out said cable on each of said cable feed means.   
     
     
       2. The system in accordance with claim 1 wherein said system includes a clock means connected to said sensor means to allow an operator to generate said signals for discrete time periods. 
     
     
       3. The system in accordance with claim 1 wherein said computer includes a memory into which an operator stores said predetermined values for said core and said layers of cable and a program means for operating on the signal inputs from said sensor means where said sensor means includes a clock means connected thereto and said predetermined values in said memory to substantially precisely calculate cable feed rate and length of cable fed out. 
     
     
       4. The system in accordance with claim 13 wherein said system includes an up/down counter coupled to each of said sensor means wherein each counter determines the direction of angular rotation of said drum means and that generates said signal inputs for said computer whereby said calculated cable feed rate can be indicated for both cable payout and infeed. 
     
     
       5. The system in accordance with claim 1 wherein said system includes a means for displaying said current cable feed rate and the length of cable fed from said drum. 
     
     
       6. A system for feeding a plurality of cable lines and for simultaneously precisely measuring length of cable feed and current feed rate of each of said cable lines comprising: a plurality of cables each having a predetermined diameter;   a plurality of rotatable drum means each having a core with a predetermined length and diameter for storing and feeding said cable, and having edge flanges for retaining said cable thereon in a plurality of layers each having a predetermined diameter and number of wraps per layer;   a plurality of drive means one for each of said drum means, suitably supported, for rotating a plurality of said drum means;   a plurality of sensor means adapted to detect angular rotation of each of said drum means and speed of rotation of said drum means and to provide signals corresponding to increments of rotation of said drum means; and   a computer means, coupled to all of said sensor means and adapted to receive inputs of said signals corresponding to said incremental angular rotation from said sensor means for providing output signals indicating feed rate and the length of cable feed from said drum means and for controlling the length of cable fed from and the current feed rate of each of said rotatable drum means, whereby said cables are attached to a drilling vessel and are controllably fed so as to cause said drilling vessel to move in a desired direction.   
     
     
       7. The system in accordance with claim 6 wherein said system includes a clock means connected to said sensor means to allow an operator to generate said signals for discrete time periods. 
     
     
       8. The system in accordance with claim 6 wherein said computer includes a memory into which an operator stores said predetermined values for said core and said layers of cable and a program means for operating on the signal inputs from said sensor means, where said sensor means includes a clock means connected thereto, and said predetermined values in said memory to calculate cable feed rate and length of cable fed out. 
     
     
       9. The system in accordance with claim 8 wherein said system includes a means for displaying said current cable feed rate and the length of cable fed from said drum. 
     
     
       10. The system in accordance with claim 6 wherein said system includes an up/down counter coupled to each of said sensor means wherein each counter determines the direction of angular rotation of an associated drum means and generates said signal inputs to said computer enabling said calculated cable feed rate to be indicated for both cable payout and infeed.